Analytical pipette.



A LOWY.

ANALYTICAL PIPETTE.

APPLICATION FILED MAR.27. I916.

Patented Nov. T, 1910.

ALEXANDER LOW, 01: NEW YORK, N. Y.

ANALYTICAL PIBETTE.

naoaaee.

Specification of Letters Patent.

Patented Nov. "Z, 1916.

Application filed March 27, 1916. Serial No. 87,114.

To all whom it may concern Be it known that I, ALEXANDER Lowr, a citizenof the United States, residing in the borough of Brooklyn, city of NewYork, county of Kings, and State of New York, have invented a new anduseful Improvement in Analytical Pipettes, of which the following is aspecification.

My invention relates to improvements in an analytical pipette,consisting of a new and modified stop-cock.

The objects of my improvement are, first, it enables the operator toautomatically control an exact measured volume of liquid sucked-up intothe pipette; second, it 0bviates the necessity of adjusting andmaintaining and manipulating the exact volume of the liquid once it haspassed the graduation mark; and third, it permits of the discharge fromthe pipette of the exact measured volume of liquid. These objects Iattain in the improved pipette shown in the annexed drawings, in whichFigure 1 shows the entire pipette with the modified stop-cock adaptableto any given volume. Fig. 2 shows the position of stopcock while theliquid is being drawn up. Fig. 3 shows the position of stop-cock afterthe stopper has been turned clock-wise 90 to that shown in Fig. 2.

Similar letters refer to similar parts throughout the several views.

Line A B (Fig. 2) is the mark of graduation.

H shows chamber below stop-cock and G shows chamber above stop-cock.

F is a cylindrical bore through stop-cock connecting chambers G and Hduring the process of suction.

E is a cylindrical bore ending back of F at an angle of 90 of which C isa continuation and ends at a slight elevation at D.

D (Fig. 3) shows place closed by thumb. In this position channel 0 isconnected with chamber H through openin E. In this position chamber G isshut 0 from chamber H. The pipette is made of glass and is adaptable toany given volume of liquid.

The operation of my improved pipette is as follows :With suction appliedat end of chamber G (Fig. 2) with mouth or any other sucking device, theliquid is drawn up through chamber H until it just passes the graduatedmark A B. The thumb is then placed on D so as to close opening Dairtight. The stopper of the stop-cock is then rota-ted clockwisethrough 90, thus bringing opening E (the continuation of tube C and D)to line of graduation A B and directly in contact with the upper opening of chamber H. The thumb is then released. Gravity now forces theexact measured volume of liquid out of chamber H. Any excess liquidsucked up beyond line A B will be entrapped in either bore F or in boreF and chamber G. This excess is returnable by revolving the stopper ofthe stop-cock counter clockwise through 90.

Said analytical pipette can be enlarged, decreased in size or otherwisealtered as to form or shape, or material or minor details ofconstruction within the scope of this invention without departing fromits spirit or sacrificing any of its advantages.

I claim In a pipette, in combination a chamber adapted to containliquid, conduits communicating with opposite sides of said chamber; astop-cock interposed in one of said conduits whereby a portion of saidconduit connects said liquid chamber and said stopcock, and a ductwithin said stop-cock adapted to establish communication between saidconnecting conduit and the atmosphere when said stop-cock is closed.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses, this 25th day of March, 1916.

ALEXANDER LOWY, PH. D.

Witnesses:

Jonas Sormm'rz, FRANK C. Ema.

